Accordng to Billboard magazine, Apple's new Music Store sold a whopping 275,000 tracks during first 18 hours of operation... That works out at over four tracks sold every second...

Billboard bases the claim for the number of Music Store tracks sold on comment from sources within major music labels.

Billboard also alleges that at least two labels have signed up for Apple's upcoming Windows version of Music Store. We'd have thought Apple would have built such a licence into its agreement with the labels from the word go, but maybe that's not the case.

Apple is charging punters 99 cents per track. It is yet to be published just how much of that goes to artists (performers and composers), how much to the labels and how much is left to Apple...

The Register's runor mill has been in full motion, with many of it's readers pointing out a recent Forbes article stating Apple takes on average 35 cents for each track it sells - so our guestimate's not so far off.

On that basis, Apple added $99,000 to its Q3 revenue tally during the first 18 hours the Music Store was open to the public. If it can keep that up throughout the quarter, it will make a significant, multi-million dollar contribution to the company's bottom line (though its own costs of sale have yet to be deducted). It's not a patch on hardware revenues, but every little bit helps in these tough times.